Control Flow in Ruby — Teaching Your Code to Make Decisions

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Control Flow in Ruby — Teaching Your Code to Make Decisions

🧭 CodeCraft Diaries #3: Control Flow in Ruby — Teaching Your Code to Make Decisions

“If coffee exists, drink it. Else, panic.”
Congratulations, you just wrote your first decision in Ruby.

Control flow is what gives your program a brain. It's how you get it to choose a path, evaluate a condition, and respond differently depending on what’s happening.

🌱 It Starts With a Question

In real life, we make decisions constantly:

  • If it’s raining, take an umbrella.
  • If your code runs, you celebrate. Else, you debug 😭.

In Ruby, we do the same using keywords like if, elsif, else, and unless.

🔄 If / Else in Action

weather = "rainy"

if weather == "sunny"
  puts "Wear sunglasses 😎"
elsif weather == "rainy"
  puts "Take an umbrella ☔"
else
  puts "Check the weather app 🤷"
end

Output: Take an umbrella ☔

Ruby reads that like a story. That’s the magic. ✨

🚫 Unless – Flip the Logic

Sometimes it’s easier to say “do this unless X happens.” Ruby gives you the unless keyword for that:

logged_in = false

unless logged_in
  puts "Please log in first 🔐"
end

Think of it as “if NOT.” It’s clean and very Ruby-ish.

✅ Comparison Operators: The Brains of Decisions

  • == → Equal to
  • != → Not equal to
  • >, < → Greater/Less than
  • >=, <= → Greater/Less or equal
age = 18

if age >= 18
  puts "You're eligible to vote 🗳️"
end

🔁 Case Statement – When You Have Many Options

role = "admin"

case role
when "admin"
  puts "Full access granted ✅"
when "editor"
  puts "Edit access only ✍️"
when "viewer"
  puts "View only 🔍"
else
  puts "No access 🚫"
end

Use case when you want to match one value against many choices.

🎯 Quick Real-World Use

user_logged_in = true
cart_items = 0

if user_logged_in && cart_items > 0
  puts "Proceed to checkout 🛒"
elsif user_logged_in
  puts "Your cart is empty 😕"
else
  puts "Please log in to continue 🔐"
end

This is the kind of logic behind real websites. Ruby makes it clear and readable.

📌 Pro Tip

"Your code should read like a conversation."
If someone else (or future-you) can’t tell what your condition is doing, rewrite it. Code is for humans, too.

📸 Visual Vibe

Control flow: the GPS of your Ruby logic 🧭

🛠️ TL;DR

  • if/else lets you branch your code based on conditions
  • unless flips the condition
  • case is great for handling many options
  • Use ==, >, != to compare values

Your Ruby journey just learned to think. Next up: it'll learn to repeat 😏

📎 Missed the Last Blog?

Check out Variables and Data Types in Ruby — where the real magic started:
👉 https://codecraftdiaries.blogspot.com/2025/05/variables-and-data-types-in-ruby.html

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